Julia a high school girl, learns that her younger sister has a bowel syndrome disorder and should undergo surgery as soon as possible. She decides to go to Texas with her two friends. But in their road trip, they get involved in some adventures.

Check out the formula page for formatting guidance. This is more like the set up than a logline because the story kinda starts when their road trip begins. Currently the two things (road trip and bowel syndrome) seem unrelated and there's ambiguity as to who the ?she? (she decides to...) is referring to. Since the bulk of the story takes place on the road trip tell us what happens there. What's their goal? What do they learn? What forces are working against them? Where's the conflict and where's the story?